Pancreatic cancer is an aggressive and highly lethal form of pancreatic malignancy. The incidence of pancreatic cancer varies greatly across regions with the highest incidence and mortality rates found in developed countries. Approximately, over 2 million people worldwide die annually due to pancreatic cancer along with a steady increasing incidence rate. Deaths from pancreatic cancer rank fourth among cancer-related deaths in the United States and it is one of the most common gastrointestinal malignancies.
Risk factors for pancreatic cancer include, among others, high-fat diet, smoking, chronic pancreatitis, primary sclerosing cholangitis, hereditary pancreatitis, family history of pancreatic cancer and diabetes mellitus. However, age seems to be a significant risk factor, and the rate of incidence is proportional with the age of the individual. Pancreatic cancer possesses some characteristics such as fast progress, high degree of malignancy and early metastasis which eventually brings poor prognosis for patients with a 5-year survival rate of only 1% to 3%.
Approximately 20% of patients are diagnosed with localized and potentially curable tumors. However, majority (95%) of the cases of pancreatic cancer are adenocarcinomas which resemble the pancreatic ductal cell. Metastasis of this cancer is generally local, most often involving the liver, lung, spleen, lymphatic system, adrenal glands and transverse colon.
Pancreatic cancer is treated in several ways, either alone or in combination based upon the stages of malignancy. Currently, surgery or resection is still the most basic means for treating pancreatic cancer for curative treatment. However, despite the fact that surgical options for pancreatic cancer are now associated with acceptable outcomes, they often prove ineffective in controlling the disease with reported recurrence rates approaching almost 80% (both locally and distant) and a 5-year survival rate of only 10%-24% for cases involving total resection.
Other treatment options of pancreatic cancer range from systemic chemotherapy alone to combined forms of treatment with chemoradiation and chemotherapy. Chemotherapy treatments can be categorized as adjuvant (treatment after surgery), neo-adjuvant (treatment prior to surgery) and palliative. The most common chemotherapeutic agents that are used to treat pancreatic cancer are gemcitabine, 5-fluouracil, capecitabine, cisplatin and oxaliplatin. These agents function on the basis of cross-linking mechanisms in which their reactive region interacts with the cell's DNA or RNA nucleotides, thus disrupting the cell cycle progression which leads to cancer cell apoptosis.
Further, targeted therapy of erlotinib in combination with gemcitabine has been approved for patients with advanced pancreatic cancer. Targeted therapy is a treatment that targets the cancer's specific genes, proteins or the tissue environment that contribute to cancer growth and survival. This type of treatment blocks the growth and spread of cancer cells while limiting damage to healthy cells.
Although some progress has been made in the management of pancreatic cancer over the years, the benefits from such treatments are considerably small and have always been confined to a minority of the treated population. Further, aggressive tumor biology and limited efficacy of conventional therapies have led to rapid progression of this disease as well as an increase in the cancer specific mortality rate. Hence, there still remains a need to develop different treatment approaches in a cost effective and a time efficient manner.